Hybrid Cryptosystem of Spritz Symmetric Algorithm and RSA Dual Modulus Algorithm in Digital File Security

Abstract

Amid the rapid development of the digital era, data protection has become very important for individuals and organizations. Digital data often contains sensitive and high-value information that needs to be protected from illegal access and cyber threats. Cryptography can be classified into two types based on the keys used, namely symmetric cryptography and asymmetric cryptography.  Spritz is an asymmetric stream cipher algorithm with encryption and decryption speed but only guarantees the security of keys 128 bits long. Dual Modulus RSA is a variant of the RSA algorithm that offers a higher level of protection compared to Spritz because of the difficulty of factoring large prime numbers during key generation. Still, the Dual Modulus RSA algorithm requires a long time in the process of encrypting and decrypting messages. So this research offers a hybrid cryptography system where the spritz algorithm is used for the message encryption process and the spritz key that is generated is encrypted using a Dual modulus RSA public key so that the key used has double security where the key generated is bigger and more random than the key previous spritz. The Dual Modulus RSA algorithm is used to decrypt the cipher key which will then produce a key spritz. This research shows that using a hybrid cryptography system can prevent the possibility of data theft because the keys used are double-secured and the encryption process is relatively faster.